Looking for
loopholes. The
impossible may just take longer and require some imagination.

There are few more hazardous occupations for a
scientist than getting in trouble with the laws of nature. These laws is
defended by a scientific community as grimly determined as Judge Dredd -- we
all know about ‘damned’ scientific data. Sometimes, though, a trial case gets
through which shows the law is more flexible than originally thought. This is
the thinking behind the Fluid Space Drive or FSD, which looks like an
outrageous attempt to defeat the law of conservation of momentum (2) but which
might be a matter of finding a loophole.

The principle of the FSD is quite simple. Imagine two
astronauts sitting at either end of a spacecraft, throwing a cannonball between
them. Each time it is thrown, the cannonball gives the spacecraft a kick in the
opposite direction, in accordance with Newton’s principle of equal and opposite
reactions. Every time it is caught, the momentum of the spacecraft and
cannonball cancel each other out again. You cannot propel a spacecraft by any
rearrangement of matter inside it, only by throwing things out – which is how
rocket engines, ion drives and other accepted propulsion systems work.

In the Fluid Space Drive, the cannonball being thrown
between the astronauts is equipped with a braking mechanism like a parachute,
which is used when it is thrown in one direction only. This means it hits one
end of the spacecraft with much greater force than the other. FSD developer
William Elliott argues that this creates an asymmetry in the momentum transfer,
so the cannonball can create a net force. It’s like a low-tech version of Roger
Shawyer’s electromagnetic EmDrive (see FT201:14).

Conventional physicists would argue that the momentum
lost by using a parachute is simply transferred to air molecules inside the
spacecraft, and while it may not be felt, the momentum will still be there.
This is similar to an old argument about whether a sealed cage with a bird in
it weighs less if the bird is hovering in the cage by flapping its wings. The
consensus is that the average downward force is exactly the same as if the bird
had been solidly perched, but not everyone agrees.

Seemingly intractable laws may turn out to have
loopholes. Elliott quotes the example of Earnshaw’s Theorem. Samuel Earnshaw
was a 19th century Yorkshire mathematician, who demonstrated the
impossibility of magnetic levitation. Although magnets can be arranged to repel
each other, Earnshaw showed that they could not remain stable in a fixed
configuration.

Earnshaw’s theorem is valid, but does have notable
loopholes. Specifically some sorts of materials and dynamic configurations –
such as a spinning magnet – can levitate successfully. Perhaps the Victorians
would not have had maglev trains anyway, but as it had been proved impossible,
they did not try.

Sometimes the apparent limitations imposed by the law
can stop research dead in its tracks, when in fact all that is needed is a
little imagination. Einstein proposed a new method for amplifying a beam of
light in 1918. This involved shining the light through a collection of hot molecules
so they all released energy at the same time. The problem was that it would
only work if there were more molecules in a higher energy state than in a lower
state (‘population inversion’). It had been established by Boltzmann that in
any stable state, the lower energy state is always more common. The conditions
required by Einstein could only met by a substance with a temperature described
by an imaginary number.

The breakthrough came in 1960 when researchers
realised that the Boltzmann limitation only applied to a stable state. By
applying a sudden flash of energy, it was possible to achieve population
inversion and the conditions described by Einstein.Theodore Maiman heated a ruby crystal with a
flash lamp and produce what would become known as the first laser.

The necessary hardware had been around for decades,
but nobody had thought to assemble it as Maiman did. Lasers have now become
ubiquitous, from broadband telecommunications to printers and supermarket
bar-code scanners. They might have been forty years more advanced if Maiman’s
insight had come sooner.

Einstein also predicted time travel, another field
which has been largely neglected because of apparently insuperable barriers.
This may also look like a failure of imagination in hindsight.

Something similar nearly happened with John Pendry’s
now-celebrated work on Metamaterials. Pendry’s insight, published in Physical
Review Letters 2000 was that a suitably structured material might be used to
create a perfect lens and to manipulate light in novel ways – for example,
diverting it around an object to create an ‘invisibility shield’. Critics
objected that this implied a negative refractive index, something which was
considered impossible, and the work must be flawed. They were quickly silenced when
the Metamaterials were constructed shortly afterwards. While negative
refractive indices are not found in natures, this does not mean that they
cannot exist.

This sort of historical background gives heart to
William Elliott and his co-workers from the University of Chile on the FSD. It
also drives thousands of garage-based inventors convinced that they alone have
the secret to the next big breakthrough. The great thing about science is that,
although it may sometimes seem as unchangeable as a religion, it does respond
to facts. Satellite propulsion is an industry worth billions and a new
technology would be hard to ignore.

Never mind the theory, set the FSD to full speed ahead
and see what happens…

(1) Fortean Times magazine
does not at present have a web page, you can see an image of the article here (http://www.wjetech.cl/a/),
David Hambling
sent me the article and gave me permission to show on this site.